A display and response tester has been designed and constructed for use in testing amnesic patients. In this study, the subjects ability to retain new information, which in this case takes the form of picture images, is being assessed for amnesic patients relative to normal control subjects. Further correlation of the mental activity stimulated by the visual image is being undertaken with brain scans performed on the PET scanner. For the testing, a sequence of single images is presented as a study set to the patient which is followed by another sequence of image pairs, one of the images in that pair was present in the study set. The patient is to select which one this was and his response is recorded. Previously, testing was performed using slide projectors to perform this task; however, unreliable operation and auditory stimuli associated with the change mechanism provided a distraction. The present system uses a microprocessor controller to drive a video tape recorder and a video display unit providing an easy to use, trouble free presentation. In addition, the controller also records the responses made by the patient and compares their final response with the correct response for accuracy. A print-out of the number of responses with timing for each image, as well as the accuracy of the response, is given at the end of the session. Further, as an aid to the examiner, a run time display is used to monitor whether or not the patient is responding to any given image. For each testing sequence a unique video tape is used, which after insertion into the unit releases the operator to perform other duties; previously the operator was required to constantly monitor the slide projectors and to change the slide trays at the appropriate point. The tester has the necessary hardware to make each video tape, and uses the audio track to label each picture for identification of responses in the testing mode.